By Sara Fitzsimmons
Regional Science Coordinator

The American Chestnut Foundation

On Saturday, April 25, several representatives from The American Chestnut Foundations (TACF) met at Aton Forest to discuss details of a summer project that is to be taken on by the Connecticut Chapter intern this summer. Christine Cadigan, a Duke University Stanback Intern, will be taking on this project starting in mid-May. More information on the intern and the project may be found at the related blog entry: Selection of Summer 2009 CTTACF Intern

[click to enlarge] photo courtesy of Sara Fitzsimmons

The mature forest of Aton Forest contains primarily hemlock and red oak. This photograph to the left was taken along the township line, the westernmost boundary of Aton Forest. The main goal for this year's summer intern project is to discover the differences in chestnut counts between two sites, Aton Forest and the Harvard Forest. Dr. Fred Paillet, now at Univ. of Arkansas, saw many similarities between these two forests, but one major difference. While there were many living sprouts at Harvard Forest, Aton Forest had very few. What Aton did have, however, were many dead stems laying on the ground. Why would these two sites, with similar overstory, apparent geology, and general ecology, have such differences in chestnut stocking? And why would Aton, a site formerly rich in chestnut, no longer support living stems?

To answer those primary questions, Dr. Paillet has proposed a study for Christine wherein she will thoroughly 1) study the landuse and history of both sites; 2) sample dead chestnut stems as well as surrounding species; and 3) and map both living and dead chestnut locations. Differences in landuse may be the easiest answer. Different management techniques can certainly affect stocking of many species. Even if differences in landuse appear to be the primary answer, sampling and mapping of the living and dead stems can still provide very useful information. Christine, Dr. Paillet, and TACF can learn about what effects geology, soil type, slope, climate, and aspect all have on long-term chestnut population survival. By looking at these sites closely, and determining why one site has sustained a living population while the other didn't, TACF may be in a better position to establish guidelines for long-term management of restoration plots. This living sprout (pictured in image to right) is along the North Colebrook Road, only a few hundred feet southeast from the main entrance to Aton Forest.

[click to enlarge] photo courtesy of Sara Fitzsimmons

[click to enlarge] photo courtesy of Sara Fitzsimmons

So, in preparation for Christine's arrival in mid-May, Dr. Paillet met with Dr. John Anderson, Executive Director of Aton Forest, Bill Adamsen, President of CT-TACF, Gayle Kida, Breeding Coordinator for CT-TACF, and Sara Fitzsimmons, TACF's Northern Appalachian Regional Science Coordinator (and former Duke Stanback Intern in 2000). The first thing we looked at were the only two living sprouts we knew about on the site as well as the only still-standing stump on the property. The photo to left shows another sprout found by Bill Adamsen during our walk. The larger stem is dead while the small sprout, being held by Fred, is barely visible.

And the only long-dead stem still standing. John is on the left with Fred in the middle. The cankered portion of this stem was removed and is now on display in the Aton Forest office.

[click to enlarge] photo courtesy of Sara Fitzsimmons

[click to enlarge] map courtesy of Sara Fitzsimmons

After looking at those individuals, the group traveled southeast to the township line, which is marked by a stone wall. From there, we traversed the contour of the slope. Below shows a draft map created using GPS coordinates taken during the tour. The living sprouts are in the upper portion of the map (marked by purple tree). The office is a big red phone. The dead stems are marked by green hexagons. Many other dead stems were observed but not sampled. The majority of those dead stems appear to be clustered up and down the south-facing slope. The "green cloud" near the living sprouts denotes an orchard of material from the Connecticut Agricultural Experiment Station.

One of the first tasks our group had to learn, and must subsequently teach Christine, is how to identify weathered chestnut wood. Chestnut wood is pretty distinct, though can be tricky until one gets a "seasoned" eye. But there are some good rules of thumb, and by the end of the day, the group were almost professionals at ID'ing downed stems.

[click to enlarge] photo courtesy of Sara Fitzsimmons

[click to enlarge] photo courtesy of Sara Fitzsimmons

The first feature of which to take note is what other species would be in the forest. In Aton, about the only species that could be large, downed wood would be white pine, hemlock, white birch, red oak, and chestnut. Each of those species are very readily distinguishable among themselves, except for red oak and chestnut. Hemlock and white birch typically decay quite quickly. White pine is highly distinguishable because it is not ring porous and should have a distinct "piney" smell for quite some time. When weathered, red oak and chestnut look very much alike and both have good rot resistance qualities. But there is one very noticeable feature difference between the two in a structure called a ray. When looking at a sample that might be chestnut, one should look very closely at the rings. On cross-sections of oak, like that to the left, red oak will exhibit very distinct white lines that bisect the growth rings. These structures are called "rays". While chestnut has these features, they are rarely noticeable to the naked eye.

Though sampling the dead wood as well as the surrounding living trees will be the only way we can determine the ages of these down stems, they have most likely been dead at least 60 or more years. Those stems in contact with the forest floor have decayed more than those stems that are up off the ground. But even those that endured for some time deteriorate more every year. The next decade or so may be one of the last opportunities for TACF to analyze the extent of pre-blight chestnut populations by sampling downed chestnut wood. Though very rot resistant, even chestnut will decay given enough time, and decay will only hasten as these stems fall to the ground.

[click to enlarge] photo courtesy of Sara Fitzsimmons

Other Photos From the Forest

The tour provided great opportunities for seeing the early forest growth.

[click to enlarge] photo courtesy of Bill Adamsen

[click to enlarge] photo courtesy of Sara Fitzsimmons

Early this spring, Aton Forest experienced serious windstorms. The tops of many older white pine and hemlocks were sheared off the trees and strewn about the forest floor. One of the more interesting sights at the site is this blow-over of three mature hemlocks.

One of the more impressive parts of this blowdown of hemlocks is the very narrow band of organic material in which the hemlocks were growing. There is generally no mineral soil on this site and the bedrock tends to sit very near the surface.

[click to enlarge] photo courtesy of Sara Fitzsimmons

Illustrations by Dr. Fred Paillet about American chestnut

Some of you may be aware that Dr. Paillet has been a major contributor to the training for the Appalachian Mountain Club Mega Transect project. Anyone who has read Dr. Paiilet's papers is aware that he is a master observer - one who draws meaningful inferences from details in the clutter of a forest floor. In recognition of this skill, and how it will be leveraged for this project, I've reproduced, with Fred's permission a series of his illustrations and accompanying descriptions of observations along some southern sections of the Appalachian Trail.

I am sure reading these notes has helped make me a better observer, and I hope it will do the same for you.

Figure 1 - [click to expand] Illustration courtesy of Dr. Fred Paillet

Figure 1. Chestnut stump along the Appalachian Trail about two miles north of Springer Mountain, Georgia. This is the old stump of a blight-killed chestnut adjacent to an AT shelter, and is compared to a living chestnut tree in the same drawing. Based on tree-ring studies from the area, this tree was killed by blight sometime between 1935 and 1940. The flat top of the stump suggests that the tree was cut in the timber salvage operations typical of that era. Compare this stump to the base of a similar-sized living chestnut in West Salem, Wisconsin. That living and vigorous canopy-dominant tree had a dwarfed basal sprout growing from the suppressed buds on the root collar. A much larger population of living European chestnut sampled in Russia shows that these dwarfed basal sprouts are not unusual even when there is no damage or disturbance to the "parent" tree. Examination of chestnut trees killed by logging in West Salem showed these little sprouts grew from "bulbs" of tissue embedded in "sockets" in the root collar. A similar socket is clearly present in the old stump in Georgia, indicating that this tree also had one or more basal sprouts even before it was stressed by blight. Studies show that chestnut root collar sprouts develop their own root systems and are largely independent of the root system of the "parent" tree. These independent little trees have a very difficult time in surviving when they are isolated by a surrounding mass of wood, explaining why most living chestnut sprouts we see today originated as old seedlings that never attained large size. At the time this figure was made, sessile trillium and bloodroot were just bursting into bloom in the leaf litter along the trail.

Figure 2 - [click to expand] Illustration courtesy of Dr. Fred Paillet

Figure 2. Chestnut sprout clone about one mile north of the AT crossing of US route 129, Neels Gap, Georgia. Most of the live chestnut sprouts observed along the AT looked like this. Sprout stems were small trees up to an inch or two in diameter and maybe 15 feet tall, occurring as single little trees or pairs of trees. They had clearly originated after a previous stem had been killed by blight, as indicated by the presence of old, deeply weathered wood from similarly sized stems. Almost all of the sprouts seen in April 2008 were recently killed by blight, or impacted by one or more active blight cankers. The incidence of blight is probably explained by the often-noted tendency for blight to occur in "epidemics". The basal sprouts produced by stems after they are girdled by blight remain small for many years. The numerous sprouts sort themselves into a small number as a result of blight, competition, and browsing. These remaining spouts are so small they provide very little substrate for the continued growth of the blight mycelia. The combination of a small "target" for the blight and the low level of blight in the area allows the regenerating sprouts to escape disease for a considerable time. The size of the stems in my figure indicate that this could be more than a decade. Eventually, the amount of chestnut bark available for blight infection reaches a point where a new epidemic can sustain itself, and the cycle continues. One wonders how many sprouts fail to make the transition under the stress imposed by blight and competition. A considerable number must be able to handle such adverse conditions because there are so many living sprouts today.

Figure 3 - [click to expand] Illustration courtesy of Dr. Fred Paillet

Figure 3. Standing chestnut snag adjacent to the AT about two miles north of Neels Gap, Georgia. Although large chestnut trees in this area must have been killed by blight before 1935, some standing chestnut snags can still be seen along the AT today. In general, there is a wide variation in the state of preservation of chestnut logs and stumps along the southern part of the AT. The remains of the old chestnut forests vary from nearly intact snags such as in my figure, to badly deteriorated slabs of chestnut wood scattered in the leaf litter. The best preservation occurs when snags remain standing, or when fallen trees are propped up off of the ground by their lower branches. When chestnut logs are in contact with moist soil, they tend to rot out from the interior. The large vessels in the outermost sapwood keep the wood well-drained and free from decay. The inner heartwood has had the conducting cells plugged with resin, and this inner core of wood retains moisture and becomes more liable to decay. In time the log becomes hollow, and then the outer cylinder collapses to form a pile of slabs. This disintegration is aided by the lack of cross-connecting ray cells, which gives chestnut logs their well-known propensity to spilt into rails. But what kept the particular chestnut tree shown in my figure upright for more than 70 years? The location had something to do with it. This is a well-drained saddle in a ridge where the forest today is white oak, mockernut hickory, and basswood. Note that the snag is almost as big as the surrounding oaks, even though they have had another 70 years of growth. The leaning oak just behind the chestnut snag must have an interesting story to tell – perhaps one of being blown over by a windstorm when no longer sheltered by the massive crown of the old chestnut.

Figure 4 - [click to expand] Illustration courtesy of Dr. Fred Paillet

Figure 4. Dwarf chestnut tree attached to the stump of a large chestnut tree along the Sutton Bald Trail, Joyce Kilmer Wilderness, North Carolina. This is the exception that proves the rule. Most chestnut sprouts we see today originated as seedlings and were never attached to a large chestnut tree. When cut or damaged, chestnut trees produced abundant root collar sprouts. When free of competition, these spouts can produce new trees, even when they come from the stumps of former timber-sized logs. In the presence of competition and repeated blight damage, chestnut sprouts find a much more difficult situation, especially since the sprout root systems are not well connected to the tissue of the main tree, and must fend for themselves. The situation is even worse when the tree dies and is left standing. Chestnut wood is very decay resistant, so the aboveground part of the tree can last for a century. The roots are kept moist in the soil, and decay more rapidly. Thus, the tree eventually topples over under its own weight. Any little sprouts perched on the root collar are pulled out of the ground in the process. In this case, the stump is in the ground and the remains show that the original tree broke off above the root collar. In fact, the stump shows several stems as if the original tree was a coppice itself. I think of a storm-battered old chestnut clump on this exposed ridge. Sloughing branches and bark had been collecting for some time around the base of this clump of trees, forming a suitable substrate for the roots of the sprouts. The dwarfed chestnut sprouts that manage to live today show the continued rigors of life on an exposed ridge, but probably survive just because of those unusual conditions. Note how the shape of these stressed sprouts differs from that of most others, and that the small stems have the characteristic bark of mature trees.

Figure 5 - [click to expand] Illustration courtesy of Dr. Fred Paillet

Figure 5. Vigorous chestnut sprout with fully healed hypovirulent cankers near the Wolf Laurel Trailhead, Joyce Kilmer Wilderness, North Carolina. Most of the chestnut sprouts seen today along the AT do not have the opportunity to become very large before blight cuts them down to size. Occasionally the fates decree that a combination of circumstances allow a chestnut sprout to reach substantial proportions. The tree in my illustration seemed perfectly healthy and had obviously been growing under almost full release. Death of a nearby oak had opened the canopy and this sprout clone was taking full advantage of the fact. Other chestnut sprouts in the area were being affected by blight, and this tree had a prominent blight canker on each of the three main stems. But the stems themselves showed no signs of stress. The crown was in the first stages of breaking bud, there were no basal sprouts being released, and no "water shoots" from the vicinity of the cankers. The cankers themselves seemed to have healed naturally, with a small patch of exposed dead wood surrounded by thick callous tissue. The "dead" oak associated with the release was cut in a logging operation some time ago. I think that the old piece of dead wood in the center of the sprouts was actually the stem released by the logging. This stem must have grown rapidly for perhaps a decade before being killed by blight. The canopy had still not closed, and so the basal sprouts stimulated by blight destruction of the main stem were able to grow under nearly full capacity. This process would account for the fact that the oak stump seems much older than the decade required to produce the chestnut stems we see today. Also note the recently dead chestnut stem off to the side. This is probably a sprout released with the three others, but left behind by the exuberant growth.

Figure 6 - [click to expand] Illustration courtesy of Dr. Fred Paillet

Figure 6. Dense population of chestnut sprouts along a well-drained ridgetop, Slickrock Creek Wilderness, North Carolina. One of the often-noted characteristics of chestnut sprouts in our forests today is the tendency for sprouts to be clustered at particular locations. This is a typical example from the kind of clustering that was apparent at several locations along the AT in Georgia and North Carolina. This site was on the crest of a northwest-facing ridge dominated by dry oak-hickory forest with no identifiable remains of large pre-blight chestnut trees. None of the sprouts in the illustration appear attached to remains of larger trees, and all are assumed to have originated as "old seedlings". I have deleted all other small stems (sassafras, red maple, and spindly mountain laurel) from my drawing so that the six small trees in the figure are all chestnut. Only the tiny little sprout off to the right is unblighted –an illustration of how small targets can escape the blight. The average spacing between chestnut sprouts here is about 6 feet. What accounts for such "hot spots" of chestnut sprout occurrence? Is this an artifact of seedling establishment, seed predator dispersal, protection from browsing, or differential survival from a much denser original population? If we knew the answer, we might have a real step forward in planning the re-introduction of chestnut to our forests.

Concerns over the role of pests in potentially transforming our landscape and even threatening the restoration of the American chestnut have never been greater. Those involved in breeding for blight resistance are concerned not just about cryphonectria parasitica (chestnut blight) but also about breeding for resistance to other exotic pathogens such as Phytophthora cinnamomi and pests such as the Asian Longhorned Beetle as well as others known and yet to come.

I was therefore interested to see a news release by the US Endowment for Forests and Communities describing a new broad-based initiative specifically targeted to the American chestnut. In their words ...

The partnership is designed to assess the potential to develop and deploy scientifically-sound, socially acceptable and rigorously vetted/regulated approaches that might see the benefits of biotechnology used in the fight against the ever increasing list of alien pests and diseases that threaten North America's forests.
...
The partnership – "Advancing Forest Health through Biotechnology" -- is a three-year perhaps $10M effort that will use the American chestnut as the test tree. The Endowment has pledged $1M to the effort and will serve on the Steering Committee along with other core funding partners, the USDA Forest Service and Duke Energy.

The US Endowment for Forests and Communities is affiliated with the Forest Health Initiative which supports protecting trees (the American chestnut) through the pathways including: breeding, genomics and transformation. The Forest Health Initiative has an affiliation with The American Chestnut Foundation - though I am not familiar with all the terms of that association.

This is very exciting news! Several years ago Dr. Chuck Maynard presented his transgenic chestnut work to the CT Chapter and we found his work to be exciting, optimistic, and positively brimming with potential. Pragmatically, it appears this approach is still in the formative and proving phase, though success is eagerly anticipated.

Restoration is a complex problem solving not just today's ecological challenges but also those of tomorrow. Peer reviewed and accepted solutions provides great hope for success. Funding a balanced solution - the pathways previously mentioned - plus significant planning for the restoration phase, should provide the best path for success.

My affiliation with the chestnut restoration community gives me great confidence that we have the intellectual power to find and implement the right solutions. Scientists such as Fred Hebard, Kim Stiener, Chuck Maynard (and many others) have devoted their careers to the research of solutiona to the decimation caused by pathogens such as the Chestnut blight. Leveraging the strengths of these collective individuals, and funding their vision will ensure that we are the eventual beneficiaries.

This partnership with the USFA, Duke Energy and US Endowment is just another welcome milestone in supporting the type of scientific efforts needed to move us to the restoration phase with a true hope for success.

This summer, after five trees we hoped to pollinate did not work out, we went forward with creating lines from four new trees and made two re-pollinations. Between June 16 and June 29 flowers were pre-bagged to protect them from stray Chinese or hybrid chestnut pollen. Controlled pollinations were done June 27 to July 11, using pollen from selected third backcross trees at TACF’s Meadowview Research Farms.

Board members Robert Gregg and David Bingham produced the year’s best results. Robert went aloft in Ken Fries’ bucket truck and performed the bagging and pollination of a tree on his property. Although only 14 bags could be placed, Robert averaged 1.8 fertile nuts per bur, harvesting 34 nuts. Next year he plans to complete the line. David spent many hours up on ladders as he also did all the pollination work himself on two trees. He brought in the biggest harvest, 88 nuts from the Old Lyme Library tree. David also finished the Salem line with an additional 18 nuts.

At Lockwood Farms in Hamden, Dr. Anagnostakis gave permission for TACF Regional Science Coordinator Leila Pinchot to pollinate a pure American tree that was planted in 1988, kept alive with the help of hypovirulence. This tree is the offspring of a tree found in Norwich. TACF Regional Science Coordinator Kendra Gurney did the harvest, but found squirrels had torn into the bags, reducing the harvest to 35 nuts.

Our Tolland and Litchfield mother trees were very badly blighted, but Bartlett Tree Experts was willing to donate their time to give the trees a chance. Mike McGee had found the Tolland tree and worked with the owner to coordinate the pollination, and I assisted with Tolland and coordinated Litchfield. Unfortunately the Tolland tree’s cankers cut off nourishment to most of the tree before the nuts were formed, so only two fertile nuts were found in the bags. The Litchfield tree did slightly better, but its topmost branches holding many bags died back. Within the twelve remaining bags were 23 nuts.

We are looking forward to completing our twenty lines of Clapper resistance backcross trees in 2009. Our board members will be busy come late May through early June next year, checking twenty reports we have received of potential mother trees in Connecticut!

Gayle Kida

With the change in Regional Science Coordinators, there is a change in process for validating chestnut samples for determining parentage.

Samples will be mailed to

Kendra Gurney
TACF New England Regional Breeding Program
USDA Forest Service Northern Research Station
705 Spear Street
South Burlington, VT 05403
Tel: 802.951.6771 x1440 Fax: 802.951.6368
Cell: 802.999.8706
Kendra@acf.org or kgurney@uvm.edu

Kendra will send the samples on to either Fred and or Sara and other sources if required to validate.

Please be sure to include several attached leaves and twig/stems to aid in validation. Attached is a short "check list" we use to help determine if the sample is indeed American chestnut, or Chinese, Japanese, European or a hybrid.

Jonathan Palmer
jmpalmer@plantpath.wisc.edu
all material is protected by copyright

Mycorrhizae: What are they and what do they do?
The success of any plant species such as chestnut is dependent upon environmental conditions such as soil pH, soil porosity, water availability, light availability, and so on. Also important are the mycorrhizal fungi present in the soil. "Myco" means fungus and "rhiza" means root, so mycorrhiza literally means "fungus-root." The mycorrhizal association was first recognized and described by Albert Bernhard Frank in 1885, although even Theophrastus of ancient Greece reported seeing this unique relationship. Mycorrhizal fungi form mutualistically beneficial relationships with the roots of 90% of all plants by providing increased uptake of nutrients such as nitrogen, potassium and phosphorus. In return, the fungi receive sugars from photosynthesis of the plant host (symbiont). In most cases, plants are dependent on mycorrhizae for survival.

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